Infrared sensors allow contactless detection of infrared rays radiated and emitted from an object to be measured. Such sensors have been conventionally used as a temperature sensor.
For example, Patent Citation 1 discloses an infrared sensor comprising: a resin film placed in a support body; a temperature sensor device for detection of infrared rays, which is provided in the resin film and detects the infrared rays passing through an optical guide portion; and a temperature sensor device for temperature compensation, which is provided in the resin film, is shielded from the infrared rays, and detects the temperature of the support body.
In this infrared sensor, an infrared absorbing film is formed on the interior surface of the guide portion. Also, the resin film contains an infrared absorbing material such as carbon black to enhance its infrared absorption.
Additionally, a film type thermistor is employed as the infrared sensors for detection of infrared rays and for temperature compensation.
Further, Patent Citation 2 discloses an infrared sensor comprising: a temperature sensor device for detection of infrared rays, a temperature sensor device for temperature compensation, a resin film to fix these devices firmly, and a casing. The casing has a frame body wherein: the temperature sensor device for detection of infrared rays is placed at the infrared incident aperture side; and the temperature sensor device for temperature compensation is placed at the shield portion side which blocks infrared rays.
In this infrared sensor, the resin film contains an infrared absorbing material such as carbon black to enhance infrared absorption of the resin film; and the frame body is made from a material having good thermal conductivity to reduce the temperature gradient between the temperature sensor devices for detection of infrared rays and for temperature compensation.
Additionally, a radial leaded type thermistor with lead wires directly connected with the thermistor device is employed for both temperature sensor devices for detection of infrared rays and for temperature compensation.